| Objective:Burn-blast combined injury is burns and defense two separate injury factors superposition in the body at the same time a compound damage form, its high mortality, illness weight, therefore clinical problems to be solved.Acute lung injury /acute respiratory distress syndrome is burned at burn-blast combined injury is one of the main causes of early death. Alveolar surface active substances(Pulmonary surfactant, PS) is secreted by alveolar type II epithelial cells of a kind of lipoprotein, with lower alveolar surface tension, maintain alveolar stability, prevent pulmonary edema, improve oxygenation.This experiment through the establishment of simulated real burn-blast combined injury model of rats, combined with the application of exogenous alveolar surface active substances, discusses its burn-blast combined injury of acute lung injury and provide experimental basis for clinical treatment of acute lung injury and theoretical basis.Methods:Selected 300 male SD rats, severe burn-blast combined injury model is established, by using the stochastic indicator method is divided into sham injury(S) group, the burn-blast combined injury treatment group(T) and control group(C).Main body experiment in each group before injuries 0 h and 6 h, 24 h, 48 h, 72 h after injury when a total of five observation point to observe, portable blood gas analyzer line of blood gas analysis were used to detect; Application of rat lung function instrument determination of rat lung function; By immune histochemical method to detect lung tissue myeloperoxidase, myeloperoxidase expression; Lung tissue pathology observation its morphological changes; The changes of TEM to observe the ultrastructure of lung tissue; Change in Western Blot method lung surface active substance binding protein A.Results:1. Change in boold gas analysis: T group PaO2 obviously higher than the C group at the each timepoint(P<0.05). T group Pa CO2 was lower than that of C group(P<0.05). T groups LAC was higher than that of C groups(P<0.05). 2. Change in lung function: Deep inspiratory capacity, tissue elasticity,central airway2. Change in lung function: Deep inspiratory capacity, tissue elasticity,central airway resistance, lung compliance, treatment group was significantly better than control group at 24 h(P<0.05). And it was no statistically significant difference(P>0.05).3. Change in MPO: T groups and C groups lung tissue MPO were higher than S groups. C groups lung tissue MPO higher than T groups, and B groups have a high degree of infiltration.4. Change in Pathological: At the timepoint 24 h of C groups lung tissue mainly for local alveolar structure, alveolar cavities and disappeared, substantial change, hyperplasia of fibrous tissue cells, plasma cells, lymphocytes, and neutrophil infiltration, there are have a pace of alveolars, alveolar epithelial cells fall off. alveolar interval swelling, bleeding, swelling in the bronchial epithelium, progressive increase of pulmonary hemorrhage and pulmonary edema,is the most serious. T groups were obviously better than C groups, which the post of alveolar cavity structure, neutrophil infiltration, lymphocytes, plasma cells, edema.5. Change in TEM: S groups were the normal lung tissue ultrastructure, AEC Ⅱ visible nucleus, chromatin evenly, nuclear membrane boundary is clear. Cell membrane surface have whole of microvilli, cytoplasmic contains many organelles, and numerous lamellar corpuscle, endoplasmic reticulum and mitochondria. AEC Ⅱ series of significant changes at the T groups and C groups. At the timepoint of 6 h T groups were with neutrophil infiltration, and lamellar corpuscle emptying relatively less than C groups. At the timepoint of 24 h T groups compared with C groups were less inflammatory cells and lamellar corpuscle density increased, the volume is uniform, round nucleolus arrangement. At the timepoint of 48 h T groups were better than C groups which alveolar cavity structure, lamellar corpuscle emptying, have not huge lamellar corpuscle. At the timepoint of 72 h P groups of lamellar corpuscle slightly increase, have not huge lamellar corpuscle.6. Change in alveolar epithelial cells of the TUNEL: At the timepoint of 6h, T group positive rate is 0.156,and C group is 0.410; At the timepoint of 24 h,T group positive rate is 0.129, and C group is 0.340; At the timepoint of 48 h, T group positive rate is 0.105, and C group is 0.307; At the timepoint of 72 h, T group positive rate is 0.110, and C group is 0.316. T group positive rate less than C group.7. Change in Western Blot: SP-A of T group and C group significantly lower than the sham groups from the timepoint of 6h. Two groups compare, P group significantly higher than B group(P>0.05).Conclusion: Exogenous pulmonary surfactant can improve oxygenation and alleviate pulmonary edema and pulmonary capillary membrane permeability of rats with severe burn blast combined injury. |
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